BD-ROM playback devices can play back, in conjunction with a content recorded in a BD-ROM, an application program (hereinafter, referred to as just an “application”) downloaded from a server device on a network. This conjunction can give users a new enjoyment to playback contents recorded in BD-ROMs. Since such an enjoyment cannot be realized in conventional DVD-Videos, manufacturers of BD-ROM playback devices hope to popularize playback of contents recorded in BD-ROMs in conjunction with applications supplied on network to make BD-ROM playback devices widespread among many users.
As a related art, Japanese Patent Application Publication No. H10-3459 and Japanese Patent Application Publication No. H10-69511 disclose an art for playing back data recorded in an optical disc in conjunction with data received from a server device on a network.